Lipid-Stabilized Water-Oil Interfaces Studied by Microfocusing Small-Angle X-ray Scattering

Area of Science:

• Materials Science
• Biotechnology
• Physical Chemistry

Background:

• Water-in-oil (w/o) emulsions are crucial in food, drug delivery, and cosmetics.
• Interfacial properties significantly impact emulsion stability and function.
• Microfluidic techniques enable precise fabrication of monodisperse emulsion droplets.

Purpose of the Study:

• Investigate the structural characteristics of w/o emulsion interfaces.
• Understand the role of phospholipids and dopants in interfacial film formation.
• Determine principles for guiding microfluidic emulsion stability.

Main Methods:

• Microfluidic device for w/o emulsion generation.
• Microfocused small-angle X-ray scattering (μ-SAXS) for structural analysis.
• Utilized phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and intercalating amphiphiles.

Main Results:

• Phospholipids form a stable, versatile boundary film (∼100 μm) composed of swollen, uncorrelated DMPC bilayers.
• Interfacial film structure is tunable by incorporating dopants with varying packing parameters.
• Cholesterol increases lipid membrane stiffness and induces interbilayer correlation.

Conclusions:

• Phospholipids create robust interfacial layers in microfluidically generated w/o emulsions.
• The structural properties of these interfacial films can be precisely controlled.
• Understanding interfacial behavior is key to designing stable and functional emulsions for advanced applications.